Changed how icons are started. Previously, ede-desktop would extract content from .desktop Exec key and explicitly run it. This would not correctly handle other .desktop details, like startup notification or running in terminal. Now, full .desktop path is sent directly to ede-launch which will take care about named startup details.
These changes also fixes bug #235: "Working directory and startup notification for desktop icons".
Editing will be done simply by creating first .desktop file and letting ede-desktop to read it, performing some
checks to determin if only content was changed or file was renamed. Using this scheme, beside it simplify the code,
it addresses the cases when icon was modified outside the desktop or removed.
These things could be solved by using DirWatch, but I'm trying to rely less on OS notification system...
By default, 'empty' icon should be used. It is now shown in preview box and will
be selected when icon wasn't explicitly chosen. Also, redraw full desktop when icon was removed, to
prevent displaying icon which isn't available.
Added small delay when icon was removed so directory watcher skip remove event.
